Two gifted 18th-century Londoners, Lord Charles Cavendish and his preeminent son, the Honorable Henry Cavendish, were descendants of paired revolutions, one political and the other scientific. Scions of a powerful revolutionary family, they gave a highly original turn to their understanding of public service. Lord Charles began his career as a Member of Parliament and ended it as an officer of the Royal Society, and his son Henry made a complete life within science, in the course of which he demonstrated skills that rank him with the greatest scientists of all time. In the history of British...